Ninecent Corporation has a target capital structure of $75$ percent common stock, $10$ percent preferred stock, and $15$ percent debt. Its cost of equity is $10$ percent, the cost of preferred stock is $6$ percent, and the pretax cost of debt is $7$ percent. The relevant tax rate is $22$ percent.

a$.$ What is the company's WACC?

Note: Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

b$.$ What is the aftertax cost of debt?

Note: Do not round intermediate calculations and enter your answer as a percent rounded to $2$ decimal places, e$.$g$.,32\mathrm{.}16.$

$\backslash$table$[[$a$.$ WACC,$\%$